Implantable neurostimulator devices including both non-rechargeable and rechargeable batteries and methods of use therewith

ABSTRACT

An implantable neurostimulation (INS) device includes a non-rechargeable battery, a rechargeable battery, an antenna, an inductive coil, a neurostimulation module and a telemetry module. The neurostimulation module produces neurostimulation signals for delivery to target neural tissue, and the telemetry module wirelessly communicates with a non-implantable device using at least one of the antenna and the inductive coil. The non-rechargeable battery provides power to the neurostimulation module, and the rechargeable battery provides power to the telemetry module. The INS device also includes a charge module that charges the rechargeable battery in dependence on signals received from a non-implantable device via the inductive coil. Additional modules, such a sensor module, can be powered by the rechargeable battery. Additionally modules, such as controller, can be powered by the non-rechargeable battery. The rechargeable battery can power components normally powered by the non-rechargeable battery, when a capacity of the non-chargeable battery falls below a threshold.

PRIORITY CLAIM

This application claims priority to U.S. Provisional Patent ApplicationNo. 61/932,454, filed Jan. 28, 2014, which is incorporated herein byreference.

FIELD OF THE INVENTION

Embodiments of the present invention generally pertain to implantableneurostimulator (INS) devices that include both a non-rechargeablebattery and a rechargeable battery, and methods for use therewith.

BACKGROUND OF THE INVENTION

An electrically operated implantable neurostimulator (INS) device can beused, e.g., to stimulate a patient's spinal cord or brain to treatvarious disorders, including, but not limited to, pain or epilepticseizures. For example, neurostimulation delivered using an INS devicehas become an accepted treatment for patients with chronic pain in theirback and/or limbs who have not found pain relief from other treatments.In general, such neurostimulation comprises applying an electricalcurrent to nerve tissue in the pathway of the chronic pain. This createsa sensation that blocks the brain's ability to sense the previouslyperceived pain. An INS device can be a spinal cord stimulator (SCS) thattreats chronic pain by delivering stimulation pulses to a patientsspinal cord to induce paresthesia in regions of a patient's body thatare afflicted by chronic pain. For a more specific example, an INSdevice can be used to selectively stimulate one or more target dorsalroot ganglion (DRG), as disclosed in U.S. Pat. No. 7,450,993, entitled“Methods for Selective Stimulation of a Ganglion,” which is incorporatedherein by reference. Other types of INS devices deliver deep brainstimulation, cortical stimulation, cochlear nerve stimulation,peripheral nerve stimulation, vagal nerve stimulation, sacral nervestimulation, and the like. Such INS devices are typically implanted inthe upper buttock or abdomen (under the skin) of patient's, but are notlimited thereto.

An electrically operated INS device needs a power source. Someelectrically operated INS devices are powered by a primary cell(commonly referred to as a non-rechargeable battery). When the batteryof such an INS device is depleted, the device must be explanted suchthat its battery can be replaced or a new INS device with a new batterycan be implanted. Other electrically operated INS devices includesecondary cells (commonly referred to as rechargeable batteries). Therechargeable battery of such an INS device can be recharged using anon-implanted device. For example, the INS device and the non-implanteddevice can include inductive coils that enable power to be wirelesslytransferred, through a patient's skin, from the non-implanted device tothe INS device for the purpose of charging the rechargeable battery.

Many electrically operated implantable neurostimulation devices arecapable of communicating with a non-implanted device, such as anon-implanted clinician programmer and/or a non-implanted patientprogrammer. Such electrically operated INS devices and non-implantedprogrammers often include an antenna or an inductive coil that enablescommunication signals to be wirelessly transferred therebetween througha patient's skin.

SUMMARY OF THE INVENTION

Embodiments of the present invention generally pertain to INS devices,and methods for use therewith. In accordance with an embodiment, an INSdevice includes an antenna, an inductive coil, a neurostimulation modulethat produces neurostimulation signals for delivery to target neuraltissue via one or more implantable leads, and a telemetry module thatenables wirelessly communicates with a non-implantable device using atleast one of the antenna and the inductive coil. Additionally, the INSdevice includes a non-rechargeable battery that provides power to theneurostimulation module, and a rechargeable battery that provides powerto the telemetry module. The INS device also includes a charge modulethat charges the rechargeable battery in dependence a power signalreceived from a non-implantable device via the inductive coil.

In accordance with an embodiment, the telemetry module uses the antennato wirelessly communicate with a non-implantable device. Additionally,the telemetry module uses the inductive coil to providebackup-communication with a non-implantable device and/or to initiate acommunication session with a non-implantable device.

In an embodiment, the INS device includes a central processing unit(CPU) that receives or otherwise accesses stimulation data that definesthe stimulation signals deliverable by the neurostimulation module viaone or more implantable leads. The rechargeable battery provides powerto the CPU when the CPU is in a low-power mode, and the non-rechargeablebattery provides power to the CPU when the CPU is not in the low-powermode (i.e., when the CPU is in its normal power mode).

In an embodiment, the INS device also includes a sensor module thatincludes a sensor (e.g., an accelerometer) that detects at least one ofmotion or position. The rechargeable battery also provides power to thesensor module. The sensor module can also include an analog-to-digitalconverter (ADC) that converts an analog signal output by the sensor ofthe sensor module to a digital signal. The ADC is also powered by therechargeable battery.

In an embodiment, the charge module that charges the rechargeablebattery is capable of powering other modules of the implantableneurostimulation device while receiving, via the inductive coil, a powersignal from a non-implantable device. Such a power signal can bemodulated to have data embedded therein, in which case the power signaltransferred between the inductive coil of the non-implantable device andthe inductive coil of the INS is also a communication signal.

In an embodiment, a volume occupied by the rechargeable battery isbetween approximately 1% and 20% of a volume occupied by thenon-rechargeable battery.

In an embodiment, an amp-hour rating of the rechargeable battery isbetween approximately 0.5% and 10% of an amp-hour rating of thenon-rechargeable battery.

In an embodiment, the rechargeable battery is used to power modules thatare normally powered by the non-rechargeable battery, when a capacity ofthe non-rechargeable battery falls below a specified threshold level.

This summary is not intended to be a complete description of the variousembodiments of the present invention. Other features and advantages ofthe embodiments of the present invention will appear from the followingdescription in which the preferred embodiments have been set forth indetail, in conjunction with the accompanying drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exemplary system including an electricallyoperated INS device that includes both a non-rechargeable battery and arechargeable battery in accordance with an embodiment of the presentinvention.

FIG. 2 illustrates exemplary details of the controller of the INS deviceintroduced in FIG. 1, according to an embodiment.

FIG. 3 is a high level flow diagram that is used to summarize a methodaccording to an embodiment of the present invention.

DETAILED DESCRIPTION

The following description is of the best modes presently contemplatedfor practicing various embodiments of the present invention. Thedescription is not to be taken in a limiting sense but is made merelyfor the purpose of describing the general principles of the invention.The scope of the invention should be ascertained with reference to theclaims. In the description of the invention that follows, like numeralsor reference designators will be used to refer to like parts or elementsthroughout. In addition, the first digit of a reference numberidentifies the drawing in which the reference number first appears.

As mentioned above, most INS devices include and are powered by either anon-rechargeable battery or a rechargeable battery. An advantage of anINS device being powered by a non-rechargeable battery is that anon-rechargeable battery typically has much higher energy and powerdensities than a rechargeable battery. Additionally, the patient doesnot have to remember to, and be burdened to, periodically recharge anon-rechargeable battery. However, a disadvantage of an INS device beingpowered by a non-rechargeable battery is that when the non-rechargeablebattery is depleted, the device must be explanted such that its batterycan be replaced or a new INS device with a new battery can be implanted.An advantage of an INS device being powered by a rechargeable battery isthat when the rechargeable battery is depleted, the battery can berecharged without explanting the INS device, potentially reducing howoften the INS device must be explanted. Certain embodiments of thepresent invention, described herein, are directed to an INS device thatincludes both a non-rechargeable battery and a rechargeable battery inorder to obtain the advantages of each type of battery and overcome thedisadvantages of each type of battery. An example of such an INS deviceis shown in FIG. 1, which is described below.

Referring to FIG. 1, illustrated therein is a system that includes anINS device 120 that includes both a non-rechargeable battery 146 and arechargeable battery 136. The INS device 120 is also shown as includingan antenna 122, an inductive coil 126, a charge module 130, a powerconverter 138, a telemetry module 140, a power converter 148, acontroller 150, a neurostimulation module 160, connector terminals 170,and a sensor module 180. The charge module 130 is shown as including arectifier 132 and a voltage regulator 134. The rechargeable battery 136can be, e.g., a lithium ion battery, but is not limited thereto. The INSdevice 120 is also shown as including coupling capacitors C1 and C2,which can also be referred to as DC blocking capacitors since they areused to block DC signals and pass AC signals.

The INS device 120 is capable of communicating with an externalprogrammer 104 (that can be a clinician programmer or a patientprogrammer) using the antenna 122 of the INS device 120. Also shown inFIG. 1 is an external device 110 that includes an inductive coil 116that can be inductively coupled to the inductive coil 126 of the INSdevice 120. As will be described in additional detail below, such aninductive coupling can be used to enable the INS device 120 to receivepower from the external device 110, charge the rechargeable battery 136of the INS device 120 and/or provide for communication (e.g., backupcommunication) with the external device 110.

The external programmer 104 can be used to program and/or adjustparameters of the INS device 120. The external programmer 104 includesan antenna 106 that is used to transmit wireless signals to, and/orreceive wireless signals from, the antenna 122 of the INS device 120. Inother words, the INS device 120 can perform wireless far fieldcommunication with the external programmer 104.

The INS device 120 can perform such wireless far field communicationwith the non-implantable device 104 using the Medical ImplantCommunication Service (MICS) standard, which was defined by the U.S.Federal Communications Commission (FCC) and European TelecommunicationsStandards Institute (ETSI). The MICS standard uses the RF band between402 and 405 MHz to provide for bi-directional radio communication withimplantable medical devices (IMDs), such as an INS device. The RF bandbetween 402 and 405 MHz can be broken down into multiple channels, e.g.,into ten 300 kHz wide channels, but not limited thereto. In 2009 the FCCbegan referring to the RF band between 402 and 405 MHz as being part ofthe 401 to 406 MHz Medical Device Radio communications (MedRadio)Service band. Accordingly, the RF band between 402 and 405 MHz can bereferred to as the MICS/MedRadio band, and the communication standardsrelating to the MICS/MedRadio band can be referred to as theMICS/MedRadio communication standards. Alternatively, the INS device 120can perform wireless RF communications with the non-implantable device104 using the Industrial, Scientific and Medical (ISM) radio bands. Theuse of other standards and frequency bands are also possible. Forexample, the INS can perform wireless communication with anon-implantable device 104 using the wireless Bluetooth™ protocolstandard, but is not limited thereto.

The external device 110, which can also be referred to as anon-implanted or non-implantable device, is shown as including a powersupply 112, driver circuitry 114 and an inductive coil 116. The powersupply 112 can be, for example, a battery or circuitry that converts ACpower received from an AC power outlet to DC power. The driver circuitry114 can be circuitry that drives the inductive coil 116 with an ACsignal for the purpose of recharging, powering and/or communicating withthe INS device 120. Accordingly, the driver circuitry 114 can, forexample, include a DC-to-AC converter as well as communicationcircuitry. If used for communication, the driver 114 can be referred toas a telemetry module. While not specifically shown, the external device110 can also include a controller, which can part of or separate fromthe driver circuitry 114. Additionally, the external device 110 caninclude further components or modules, such as a user interface.Similarly, the external programmer 104 can include additional modules,such as a controller and a user interface. While shown as two separatedevices, the external programmer 104 and the external device 110 can beimplemented as a single external device that includes both an antennaand an inductive coil. Since embodiments of the present inventionprimarily relate to INS devices, not external devices, additionaldetails of the external programmer 104 and the external device 110 arenot provided. Further, it is noted that either of the devices 104 and110 can be referred to as an external device, a non-implanted device ora non-implantable device.

The telemetry module 140 of the INS device 120 is shown as including anear field module 142 and a far field module 144. The near field module142 can be a near field transceiver, a near field transmitter or a nearfield receiver. In other words, the near field module 142 enables nearfield wireless communication between the INS device 120 and the externaldevice 110 using the inductive coil 126 of the INS device 120. Toachieve such near field communication, the inductive coil 126 of the INSdevice 120 should be within a few centimeters of the inductive coil 116of the external device 110. The far field module 144 can be a far fieldtransceiver, a far field transmitter or a far field receiver. In otherwords, the far field module 144 enables far field wireless communicationbetween the INS device 120 and the external device 104 using the antenna122 of the INS device 120. To achieve such far field communication, theantenna 122 of the INS device 120 should be within a few meters of theantenna of the external programmer 104. Accordingly, far fieldcommunication can be achieved over a greater distance than near fieldcommunication, as the terms imply. Further, the far field communicationprovides for higher speed communication than the near fieldcommunication.

The near field module 142 and the far field module 144 are each coupledto the controller 150, either directly, via separate buses, via a sharedtelemetry data bus, or in some other manner. While shown as two separateblocks, the near field module 142 and the far field module 144 can sharecertain hardware and/or firmware. For example, while the near fieldmodule 142 and the far field module 144 may have their own hardwareand/or firmware to implement their respective physical and data linklayers, they may share hardware and/or firmware that are used toimplement higher level communication protocol layers.

In accordance with an embodiment, the near field module 142 can be usedto perform inductive near field communication in noisy RF environments,e.g., as a backup to the far field RF communication. Additionally, oralternatively, for security and/or authentication reasons, the nearfield module 142 can be used to perform inductive near fieldcommunication to initiate a communication session, and then thecommunication can be switched to the higher speed far fieldcommunication (performed using the far field module 144) for theremainder of the communication session, so long as the far fieldcommunication link quality is adequate.

The neurostimulation module 160 produces neurostimulation signals fordelivery to target neural tissue via one or more implantable leads (notshown). The neurostimulation module 160 is shown as including one ormore pulse generator(s) 162 that is/are configured to produceneurostimulation pulses, and more generally, neurostimulation signals.The pulse generator(s) 162 may include dedicated, independent pulsegenerators, multiplexed pulse generators or shared pulse generators,which is/are controlled by the controller 150 via control signals totrigger or inhibit the neurostimulation pulses. The neurostimulationmodule 160 is also shown as including an electrode configuration switch164.

The controller 150 can control the pulse generator(s) 162 to generateneurostimulation pulses, and control the electrode configuration switch164 to couple the neurostimulation energy to selected electrodes of oneor more selected leads. Additionally, the controller 150 can control theelectrode configuration switch 164 to select different electrodeconfigurations for delivery of stimulation energy from the pulsegenerator(s) 162. More specifically, the controller 150 can control thepulse generator(s) 162 and the electrode configuration switch 164 todeliver stimulation energy in accordance with selected neurostimulationparameters, which can specify a lead, an electrode configuration for thespecified lead, and one or more pulse parameters, including, but notlimited, pulse amplitude, pulse width and pulse repetition rateparameters. The controller 150 can include one or more of amicroprocessor, a microcontroller, a digital signal processor (DSP), anapplication specific integrated circuit (ASIC), a field-programmablegate array (FPGA), a state machine, or similar discrete and/orintegrated logic circuitry. The controller 150 can further include RAMor ROM memory, logic and timing circuitry and I/O circuitry. Inaccordance with a specific embodiment, the controller 150 is implementedusing a microcontroller unit (MCU) that includes a central processingunit (CPU), memory, a direct memory access (DMA) controller, a clocksystem, a power controller, timers and input/output (I/O) ports, asdescribed below with reference to FIG. 2. While not shown, the MCU mayalso include analog-to-digital converters (ADCs) and/ordigital-to-analog converters (DACs).

The electrode configuration switch 164 can include a switch array,switch matrix, multiplexer, and/or any other type of switching devicesuitable to selectively couple connector terminals 170 of a connector(also known as a header) to the pulse generator(s) 162 and/or to sensecircuitry (not shown in FIG. 1). The distal end(s) of one or moreimplantable neural stimulation leads (not specifically shown) can beconnected to the connector.

In accordance with an embodiment, the non-rechargeable battery 146provides power to the neurostimulation module 160 and the controller150, and the rechargeable battery 126 provides power to the telemetrymodule 140 and the sensor module 180. This does not mean that thenon-rechargeable battery 146 need be directly connected to theneurostimulation module 160 and the controller 150. Rather, as will bedescribed below, a DC voltage produced by the non-rechargeable battery146 can be regulated and/or converted to one or more other voltagelevel(s) that is/are used to power the neurostimulation module 160 andthe controller 150. Similarly, a DC voltage produced by the rechargeablebattery 136 can be regulated and/or converted to one or more othervoltage level(s) that is/are used to power the telemetry module 140 andthe sensor module 180. A benefit of this configuration is that it takesadvantage of the advantages of both the non-rechargeable battery 146 andthe rechargeable battery 136. For example, if it is assumed that thetelemetry module 140 and the sensor module 180 collectively consume X %(e.g., 10%) of the total power consumed by the neurostimulation module160 and the controller 150 collectively, then this embodiment mayincrease the longevity of the INS device 120 by about X % (e.g., byabout 10%), as compared to if all of the modules within the INS device120 were powered by the non-rechargeable battery 146. Continuing withthe assumption that the telemetry module 140 and the sensor module 180collectively consume X % (e.g., 10%) of the total power consumed by theneurostimulation module 160 and the controller 150 collectively, thenthis embodiment will significantly reduce how often the rechargeablebattery 136 of the INS device 120 needs to be recharged, as compared toif all of the modules within the INS device 120 were powered by therechargeable battery 136.

The sensor module 180 can, e.g., include an accelerometer or some othersensor that detects motion and/or position, but is not limited thereto.Such a sensor may output an analog signal that is preferably convertedto a digital signal that can be interpreted by the controller 150.According, the sensor module 180 may also include an analog-to-digitalconverter (ADC) that converts an analog signal to a digital signal at aspecified sampling rate. In accordance with an embodiment, therechargeable battery 136 powers both the sensor and the ADC of thesensor module 180.

As mentioned above, the inductive coil 126 of the INS device 120 canused for receiving power signals from the non-implanted device 110, aswell as for receiving communication signals from the non-implanteddevice 110. More specifically, the inductive coil 126 of the INS device120 enables near field coupling with the inductive coil 116 of thenon-implanted device 110. When the non-implanted device 110 transmits apower signal by radiating RF power using its inductive coil, aninductive coupling between the inductive coil 116 of the non-implanteddevice 110 and the inductive coil 126 of the INS device 120 causescurrent to be induced in the inductive coil 126 of the INS device 120.This can more generally be referred to as the INS device 120 receivingthe power signal. The received power signal, which is an AC signal, isrectified by the rectifier 132 of the charge module 130. The output ofthe rectifier 132, which can be referred to as a rectified signal, issmoothed by a capacitor C3 of the charge module 130, to produce a nearlyDC voltage signal, albeit one with voltage ripple. This nearly DCvoltage signal is provided to the voltage regulator 134, which outputs asubstantially constant DC voltage signal. This substantially constant DCvoltage signal, output by the voltage regulator 134, can be used torecharge the rechargeable battery 136. It is also possible that thesubstantially constant DC voltage signal, output by the voltageregulator 134, can be provided directly to the power converter 138.

A power signal emitted by the inductive coil 116 of the external device110 to the inductive coil 126 of the INS device 120 may be distinct froma communication signal emitted by the inductive coil 116 of the externaldevice 110 to the inductive coil 126 of the INS device 120.Alternatively, data can be embedded into the power signals emitted bythe inductive coil 116 using any one of various different modulationschemes, in which case a signal emitted by the inductive coil 116 can beused for both transmitting data and recharging the rechargeable battery136 of the INS 120. In other words, a power signal and a communicationsignal can be implemented using a same signal. It is also noted thatdepending upon implementation, it is possible that that inductive coils(e.g., 126 and 116) can be used for far field communications.

The power converter 138 receives a DC voltage from the rechargeablebattery 136 (and/or from the voltage regulator 134) and, regulates,steps-up and/or steps-down this voltage to one or more voltage level(s)used for powering various other components of the INS device 120,including, but not limited to the telemetry module 140 and the sensormodule 180. Accordingly, the power converter 138 can include voltageregulator circuitry and/or voltage conversion circuitry.

The power converter 148 receives a DC voltage from the non-rechargeablebattery 146 and regulates, steps-up and/or steps-down this voltage toone or more voltage level(s) used for powering various other componentsof the INS device 120, including, but not limited to the controller 150and the neurostimulation module 160. For example, the power converter148 can provide a first voltage level to the controller 150, a secondvoltage level to the pulse generator(s) 162 and a third voltage level tothe electronic configuration switch of 164 of the neurostimulationmodule 160, wherein one or more of the first, second and third voltagelevels may or may not be the same, depending upon implementation.Accordingly, the power converter 148 can include voltage regulatorcircuitry and/or voltage conversion circuitry.

In certain embodiments, while the inductive coil 126 is receiving asignal transmitted by the inductive coil 116 of the external device 110,the power converter 138 (and/or the power converter 148) can receive avoltage output by the voltage regulator 134, in which case the powerconverter 138 (and/or the power converter 148) can power other modulesof the INS device 120 while the rechargeable battery 136 is beingrecharged. This can be useful, for example, if the rechargeable battery136 is allowed to be completely (or almost completely) depleted before arecharge is initiated. More specifically, this can allow for immediatecommunication between the external device 110 and the INS device 120,rather than needing to wait for the rechargeable battery 136 to besufficient recharged before being able to provide for suchcommunication.

As mentioned above, the controller 150 can be implemented using amicrocontroller unit (MCU). An example of such an embodiment isillustrated in FIG. 2. Referring to FIG. 2, the controller 150(implemented as a MCU) is shown as including a central processing unit(CPU) 210 connected to an address bus 212 and a data bus 214. Alsoconnected to the address and data busses 212 and 214 are memory 220, adirect memory access (DMA) controller 230, timers 240 and input/output(I/O) ports 250. Also shown in FIG. 2 is a clock system 260 that cangenerate clock signals having different frequencies that can be providedto the CPU 210 and other components of the MCU and/or other modules ofthe INS device 120. The memory 220 can include volatile and/ornon-volatile memory including, but not limited to, RAM, ROM, NVRAM,EEPROM, flash memory, and the like. Additionally, a power managementmodule (PMM) 270 is shown, which can control when the CPU 210 enterslow-power mode, and/or can control whether and when portions of theclock system 260 are at least partially disabled (to save power).Depending upon implementation, there are various different times thatthe CPU 210 may be switched from its normal power mode (i.e., not alow-power mode) to a low-power mode, and vise versa. For example, whenthe CPU 210 is in its normal power mode (i.e., not in a low-power mode),the CPU 210 may receive or otherwise access stimulation data thatdefines the stimulation signals deliverable by the neurostimulationmodule 160 via one or more implantable leads. Further, when the CPU 210is in its normal power mode (i.e., not in a low-power mode), the CPU 210may generate tables that are stored in the memory 220 and are used bythe DMA controller 230 to control stimulation events. For a morespecific example, the CPU 210 may generate and store in the memory 220,a first table that includes blocks of stimulation event datacorresponding to stimulation events that are to be performed during aperiod of time (e.g., a 0.5 sec. or 1 sec. period of time), and a secondtable that includes blocks of next stimulation event time datacorresponding to the period of time. After such tables are generated,the DMA controller 230 may use these tables to control the delivery ofneurostimulation signals, thereby enabling the CPU 210 to be put into alow-power mode in order to conserve power. This is just one example ofwhen the CPU 210 may be put into a low-power mode, which is not meant tobe all encompassing, as there are various other reasons that the CPU 210may be put into a low-power mode. In accordance with an embodiment, therechargeable battery 136 provides power to the CPU 210 when the CPU 210is in a low-power mode, and the non-rechargeable battery 146 providespower to the CPU 210 when the CPU 210 is not in the low-power mode,i.e., is in its normal power mode.

It is generally desirable that the INS device 120 be as small aspossible, since it is implanted within a patient's body. Accordingly, itmay not be practical for the rechargeable battery 136 and thenon-rechargeable battery 146 to both be full sized batteries. Rather, inaccordance with an embodiment, a volume occupied by the rechargeablebattery 136 is between approximately 1% and 20% (e.g., is about 10%) ofa volume occupied by the non-rechargeable battery 146. Further, sincethe rechargeable battery 136 is capable of being recharged, it need havean amp-hour rating as high as the non-rechargeable battery 146.Accordingly, in an embodiment, an amp-hour rating of the rechargeablebattery 136 is between approximately 0.5% and 10% (e.g., is about 5%) ofan amp-hour rating of the non-rechargeable battery 146.

In accordance with an embodiment, when a capacity of thenon-rechargeable battery 146 falls below a specified threshold level,the rechargeable battery 136 can be used to power modules that arenormally powered by the non-rechargeable battery 146. For example, areplacement indicator (e.g., an alarm and/or message sent to anon-implanted device) may be triggered when non-rechargeable battery 146falls below a replacement indicator threshold. At that point, or withina short period thereafter, the non-rechargeable battery 146 may not havesufficient capacity, and/or may not be capable of producing a sufficientvoltage, to power the modules it normally powers. To enable thepatient/user to continue to receive the benefits of the neurostimulationtherapy provided by the INS device 120, until a time that thepatient/user is able to schedule an explant/implant procedure duringwhich the INS device 120 is replaced (or at least its non-rechargeablebattery is replaced), the rechargeable battery 136 can power modulesnormally powered by the non-rechargeable battery 146, such as, but notlimited to, the neurostimulation module 160 and the controller 150.

FIG. 3 is a high level flow diagram that is used to summarize a methodaccording to an embodiment of the present invention. The steps shown atthe left in FIG. 3 are performed using power generated using anon-rechargeable battery (e.g., 146) of an INS device (e.g., 120) and/orusing a module powered by the non-rechargeable battery of the INSdevice. The steps shown at the right in FIG. 3 are performed using powergenerated using a rechargeable battery (e.g., 136) of the INS device(e.g., 120) and/or using a module powered by the rechargeable battery ofthe INS device.

Referring to FIG. 3, at step 302, a controller (e.g., 150) of the INSdevice is powered using the non-rechargeable battery of the INS device.At step 304, a neurostimulation module (e.g., 160) of the INS device ispowered using the non-rechargeable battery of the INS device. At step306, the neurostimulation module is used to produce neurostimulationsignals for delivery to target neural tissue via one or more implantableleads coupled to the INS device.

Still referring to FIG. 3, at step 312, a telemetry module (e.g., 140)of the INS device is powered using the rechargeable battery of the INSdevice. At step 314, a sensor module (e.g., 180) of the INS device ispowered using the rechargeable battery of the INS device. At step 316,the telemetry module of the INS device is used to perform wirelesscommunication with a non-implantable device (e.g., 104) via an antenna(e.g., 122) of the INS device. At step 318, the telemetry module of theINS device is used to perform wireless communication with anon-implantable device (e.g., 110) (which may or may not be the samenon-implantable device referred to at step 316) via an inductive coil(e.g., 126) of the INS device. The communication performed at step 316,using the inductive coil, can be backup communication. Alternatively, oradditionally, the communication performed at step 316, using theinductive coil, can be used to initiate a communication session, andthen the antenna can be used for the remainder of the communicationsession. At step 320, the rechargeable battery is charged in dependenceon a signal received via the inductive coil of the INS device from anon-implantable device (e.g., 110). At step 322, one or more modules(e.g., 160) (normally powered by the non-rechargeable battery) is/arepowered using the rechargeable battery, when the capacity of thenon-rechargeable battery (or an indicator of the capacity) falls below acorresponding specified threshold. Additional details of the stepsdescribed with reference to FIG. 3 can be appreciated from the abovedescription of FIGS. 1 and 2, as can additional steps of a method.

Embodiments of the present invention have been described above with theaid of functional building blocks illustrating the performance ofspecified functions and relationships thereof. The boundaries of thesefunctional building blocks have often been defined herein for theconvenience of the description. Alternate boundaries can be defined solong as the specified functions and relationships thereof areappropriately performed. Any such alternate boundaries are thus withinthe scope and spirit of the claimed invention. For example, it would bepossible to combine or separate some of the steps shown in FIG. 3. Foranother example, it is possible to change the boundaries of some of theblocks shown in FIGS. 1 and 2.

The previous description of the preferred embodiments is provided toenable any person skilled in the art to make or use the embodiments ofthe present invention. While the invention has been particularly shownand described with reference to preferred embodiments thereof, it willbe understood by those skilled in the art that various changes in formand details may be made therein without departing from the spirit andscope of the invention.

What is claimed is:
 1. An implantable neurostimulation device,comprising: an antenna; an inductive coil; a neurostimulation modulethat produces neurostimulation signals for delivery to target neuraltissue via one or more implantable leads; a telemetry module thatwirelessly communicates with a non-implantable device using at least oneof the antenna and the inductive coil; a non-rechargeable battery thatprovides power to the neurostimulation module; a rechargeable batterythat provides power to the telemetry module during one or more periodsof time that overlap with when the non-rechargeable battery providespower to the neurostimulation module; and a charge module that chargesthe rechargeable battery in dependence on power signals received from anon-implantable device via the inductive coil.
 2. The implantableneurostimulation device of claim 1, wherein the telemetry module usesthe antenna to wirelessly communicate with the non-implantable device.3. The implantable neurostimulation device of claim 1, wherein thetelemetry module uses the inductive coil to provide backup-communicationwith the non-implantable device or to initiate a communication sessionwith the non-implantable device.
 4. The implantable neurostimulationdevice of claim 1, further comprising: a central processing unit (CPU)that receives or otherwise accesses stimulation data that defines thestimulation signals deliverable by the neurostimulation module via oneor more implantable leads; wherein the rechargeable battery providespower to the CPU when the CPU is in a low-power mode; and wherein thenon-rechargeable battery provides power to the CPU when the CPU is notin the low-power mode.
 5. The implantable neurostimulation device ofclaim 1, further comprising: a sensor module that includes a sensor thatdetects at least one of motion or position; wherein the rechargeablebattery also provides power to the sensor module during one or moreperiods of time that overlap with when the non-rechargeable batteryprovides power to the neurostimulation module.
 6. The implantableneurostimulation device of claim 5, wherein the sensor module alsoincludes an analog-to-digital converter (ADC) that converts an analogsignal output by the sensor of the sensor module to a digital signal,and wherein the ADC is also powered by the rechargeable battery duringone or more periods of time that overlap with when the non-rechargeablebattery provides power to the neurostimulation module.
 7. Theimplantable neurostimulation device of claim 1, wherein the chargemodule that charges the rechargeable battery is capable of poweringother modules of the implantable neurostimulation device whilereceiving, via the inductive coil, a signal from the non-implantabledevice.
 8. The implantable neurostimulation device of claim 1, wherein:a volume occupied by the rechargeable battery is between 1% and 20% of avolume occupied by the non-rechargeable battery.
 9. The implantableneurostimulation device of claim 1, wherein: an amp-hour rating of therechargeable battery is between 0.5% and 10% of an amp-hour rating ofthe non-rechargeable battery.
 10. The implantable neurostimulationdevice of claim 1, wherein: the rechargeable battery is used to powerone or more modules that is/are normally powered by the non-rechargeablebattery, when a capacity of the non-rechargeable battery or an indicatorthereof falls below a specified threshold level.
 11. A method for use byan implantable neurostimulation device, comprising: powering aneurostimulation module of the implantable neurostimulation device usinga non-rechargeable battery of the implantable neurostimulation device;powering a telemetry module of the implantable neurostimulation deviceusing a rechargeable battery of the implantable neurostimulation deviceduring one or more periods of time that overlap with when thenon-rechargeable battery is used for powering the neurostimulationmodule; producing, using the neurostimulation module, neurostimulationsignals for delivery to target neural tissue via one or more implantableleads coupled to the implantable neurostimulation device; and wirelesslycommunicating with a non-implantable device using at least one of anantenna and an inductive coil connected to the telemetry module of theimplantable neurostimulation device.
 12. The method of claim 11, furthercomprising: charging the rechargeable battery based on a signal,received via the inductive coil of the implantable neurostimulationdevice, from the non-implantable device.
 13. The method of claim 11,further comprising: using a central processing unit (CPU) to receive orotherwise access stimulation data that defines the neurostimulationsignals deliverable by the neurostimulation module via one or moreimplantable leads; powering the CPU using the rechargeable battery, whenthe CPU is in a low-power mode; and powering the CPU using thenon-rechargeable battery, when the CPU is not in the low-power mode. 14.The method of claim 11, further comprising: when a capacity of thenon-rechargeable battery or an indicator thereof falls below a specifiedthreshold level, using the rechargeable battery to power one or moremodules of the implantable neurostimulation device that are normallypowered by the non-rechargeable battery.
 15. The method of claim 11,further comprising: powering a sensor module using the rechargeablebattery during one or more periods of time that overlap with when thenon-rechargeable battery is used for powering the neurostimulationmodule, wherein the sensor module is used to detect at least one ofmotion or position.
 16. The method of claim 11, wherein: a volumeoccupied by the rechargeable battery is between 1% and 20% of a volumeoccupied by the non-rechargeable battery; and an amp-hour rating of therechargeable battery is between 0.5% and 10% of an amp-hour rating ofthe non-rechargeable battery.
 17. A system, comprising: an implantableneurostimulation device including an antenna; an inductive coil; aneurostimulation module that produces neurostimulation signals fordelivery to target neural tissue via one or more implantable leads; atelemetry module; a non-rechargeable battery that provides power to theneurostimulation module; a rechargeable battery that provides power tothe telemetry module during one or more periods of time that overlapwith when the non-rechargeable battery provides power to theneurostimulation module; and a charge module that charges therechargeable battery in dependence power signals received from anon-implantable device via the inductive coil of the implantableneurostimulation device; a non-implantable device includingnon-implantable antenna; and a non-implantable device including anon-implantable inductive coil; wherein the telemetry module of theimplantable neurostimulation device uses the antenna of the implantableneurostimulation device to wirelessly communicate with thenon-implantable device including the non-implantable antenna.
 18. Thesystem of claim 17, wherein: the telemetry module of the implantableneurostimulation device uses the inductive coil of the implantableneurostimulation device to perform backup wireless communication with,or to initiate a wireless communication session with, thenon-implantable device including the non-implantable inductive coil. 19.The system of claim 17, wherein the non-implantable device including thenon-implantable antenna and the non-implantable device including thenon-implantable inductive coil comprise the same non-implantable device.20. The system of claim 17, wherein: a volume occupied by therechargeable battery is between 1% and 20% of a volume occupied by thenon-rechargeable battery; and an amp-hour rating of the rechargeablebattery is between 0.5% and 10% of an amp-hour rating of thenon-rechargeable battery.